Many global telecommunication service providers issue subscriber identity module (SIM) cards to their subscribers to allow individual subscribers to insert the physical SIM card within their mobile device for the purpose of gaining access to the provider's network services. A SIM is a component application of a universal integrated circuit card (UICC) “smart card,” and this can be referred to collectively as a SIM card. In function, the SIM component securely stores an international mobile subscriber identity (IMSI), along with various other cryptographic keys and credentials, which can be used for network authentication.
The network-access functionality of a SIM card can be realized by an eSIM resident on a secure element in a mobile device. The secure element can be a removable universal integrated circuit card (UICC), or an embedded UICC (eUICC) corresponding to an in-device, generally non-removable, hardware component of the mobile device. The European Telecommunications Standards Institute (ETSI) and the Global System for Mobile Communications Association (GSMA) have been responsible for standardizing many features of SIM cards, UICCs and eUICCs.
A SIM or eSIM can refer to an application component of a secure element. 2G global systems for mobile communications (GSM) technologies employ SIM applications, 3G universal mobile telecommunications system (UMTS) technologies employ USIM applications and ISIM applications for Internet Protocol (IP) multimedia subsystem (IMS) services, and 2G/3G code division multiple access (CDMA) technologies employ CSIM applications.
An eSIM may have similar application functionality to any of a SIM, USIM, ISIM, CSIM, etc., and the eSIM may be compliant with different radio access technologies. Various eSIMs may be provisioned into the secure element of a mobile device by an eSIM server associated with a particular mobile network operator (MNO). An eSIM comprises access credentials such as an International Mobile Subscriber Identity (IMSI) and a subscriber key (K). The subscriber key K is a shared secret stored only at the eSIM and at the MNO. The document “Embedded SIM Remote Provisioning Architecture,” Version 1.1, Jan. 30, 2014, GSM Association Official Document SGP.01, discusses provisioning.